BIONB 2210 First Prelim

ethology

study of behavior under natural conditions

evolutionary biology

study of history of life and processes of adaption

ecological genetics

study of genetic processes underlying behaviors that enhance reproduction. how genetics and the environment interact to drive evolution

Darwin

1. organisms could increase their numbers by a lot but they dont, so there is competition

2. vairations exist among individuals in every species

3. variance can be transmitted from parents to offspring

4. variations which impact survival and reproduction will inevitably change frequency

evolution

gene frequency change

natural selection

variable fitness and differential reproduction caused by variations of individuals (only evolutionary force predictably leading to fit between organism and environment, there are always tradeoffs to every variation)

selfish genes

genetic success instead of reproductive success, difference between replicators vs vehicles as survival machinery

proximate (tinbergen 4 levels of analysis)

immediate cause questions (how does a behavior occur)

ultimate (Tinbergen 4 levels of analysis)

long term cause question (why does a behavior occur)

mechanisms

mechanics (coding) for behavior

ontogeny

developmental processes (role of learning)

function

effect on fitness — has natural selection shaped this behavior?

evolutionary history

ancestral characters: in what context did they evolve?

the umwelt concept

world as perceived by an organism, based on its sensory abilities

photoreception

detection of light (sight in humans)

mechanoreception

detection of pressure (touch) vibrations through air or water (hearing or echolocation)

thermoreception

detection of temperature, sometimes allows animals to form images by seeing hot/cool regions

chemoreception

detection of chemical stimuli (smell or taste)

magnetoreception

detection of earth’s magnetic field

gustation

detection of dissolved chemicals

olfaction

detection of airborne chemicals (odorants)

phermones

volatile, organic, species specific compounds which affect behavior

behavior definition

any observable action or response of an organism

variation in behavior

genetic variation + environmental variation

genetic variation (& evidence to support)

single gene (discontinuous) or polygenic (may be discretely continuous, quantitative)

evidence to support: plants have variation despite common environment, mendelian segregation, phenotype x molecular associations, heritability estimates from quantitative genetics

environmental variation

developmental environment

heritability (+ equation)

proportion of phenotypic variation due to genes, refers to variable traits only

Vg = Va (variance transmitted from parents to offspring) + Vi (variation due to interaction effects of genes)

broad sense heritability

variation due to genes/total variance

narrow sense heritability (h²)

variation due to parents —> offspring/total variance

evolution —> new variants (due to what?)

mutation (new alleles) and gene flow

evolution —> change in frequency of variants in next generation (due to what?)

genetic drift and selection

mutation

permanent change to genomic sequence, causes evolution by changing allele frequencies, opposes selection

gene flow

influx of alleles from other population, opposes selection

genetic drift (might include what?)

chance changes in allele frequencies, might include chance mortality, failure to mate, differences in offspring number (when unrelated to phenotype)

from random sampling

opposes selection

bottleneck

large scale but short term reduction in population size followed by increase in pop size

fossil behavior

fossils can provide evidence about structure/function of ancestors

evolution in action

observing evolution of populations over our lifetime

arms race coevolution

adaptions and counter-adaptions accumulate evolving to fixation of one phenotype in each

red queen hypothesis

tug of war in evolution by frequency-dependent selection, but never reaches fixation

homology (traits) & homology assessment

trait possessed by 2+ species that was inherited with, or without, common ancestor

assessment: 1. similarity in body position, 2. similarity in structural detail, 3. presence of transitional forms and/or intermediate ontogeny, 4. look for fewest possible changes (earliest common ancestor)

analogy (traits)

traits that are similar in function but have independent origins (convergent traits)

animal communication definition

the provision of info from sender to receiver to modify receiver’s behavior, so that they both benefit

signal

intentional form of communication

cue

unintentional form of communication (passive features that a receiver may use, but did not evolve to benefit receiver) = eavesdropping

deception

benefits sender, but does not benefit receiver

visual ecology definition

study of how animals’ visual systems allow them to meet their ecological needs

vision (and what we want to study)

the process by which light signals from the environment are detected (availability, detection mechanics, interpretation, and behavioral influence)

light

wavelengths and photons

light environment

relative number of photons present at each wavelength (changes as you change environment like deep sea or different forrest regions)

sensitivity

extent to which an organism can detect light

photopigments

opsin (light detector, need 2+ to see spectrum) and retinal

vertebrates have rods (low light) and cones (bright light + color)

protanopia

when humans only have 2 opsins instead of thre

resolution

extent to which an organism can detect shapes

camera eye

light from different directions hits photoreceptors, images compared (high resolution during day and high sensitivity at night — tradeoff)

pigment pit eye

poor resolution (100s of eyes all over mantle - wide region of light deposited onto same photoreceptor), optimized for sensitivity

pinhole eye

smaller region of light deposited on specific photoreceptors (later developed lenses to become camera eye) (bad sensitivity and resolution)

refractive index

light bends when traveling from one material to another (eg water to air)

compound eye

ommatidia instead of rods and cones - good motion detection, low resolution

barrel eye

look up at prey overhead, maximized for sensitivity but not resolution

dragonfish eyes

can see red in deep sea (prey cannot see them when they light themselves up)

aposematic signals

signals letting others know you are unpalatable or dangerous

mimicry

when a receiver perceives a similarity between a mimic and a model and changes its behavior that provides selective advantage to the mimic

mimic

always sending signal, intentional copy of the model

model

can be sending signal or cue

cue mimicry

receiver of mimic and model can be different (trait did not evolve specifically to alter receiver’s behavior)

signal mimicry

receiver of both mimic and model is the same

deceptiveness

to what extent is the signal or cue a lie?

rewarding mimicry

low deceptiveness, positive fitness consequence as perceived by receiver

mullerian mimicry

low deceptiveness, neg fitness consequences perceived by receiver

aggressive mimicry

high deceptiveness, positive fitness consequence perceived by receiver

batesian mimicry

high deceptiveness, negative fitness consequence as perceived by receiver

positive frequency-dependent selection

fitness becomes higher as trait becomes more common in population

negative frequency-dependent selection

fitness decreases as trait becomes more frequent in population

hormones (what do they coordinate behavior with? - 4 things)

chemical messages that coordinate behavior with 1. intrinsic factors (age, gender, condition, reproductive state, etc) 2. external ecological environment (time of year, weather, food), 3. social environment

endocrine

hormone released into bloodsream

autocrine

released chemical works back onto releasing cell

paracrine

hormone acts on nearby cells

phermone

intraspecific release into environment

allomone

interspecific release into environment

primary endocrine glands

thyroid, hypothalamus, pituitary, pineal gland, thymus, adrenal cortex and medulla, pancreas, testes, ovaries, placenta

peptide hormone examples

insulin, oxytocin, growth hormone

fast acting (binds to receptors and trigger second messengers such as cAMP, cGMP, inositol triphosphate)

amine hormone examples

epinephrine, adrenaline, dopamine, melatonin, thyroid hormone

fast acting (binds to receptors and trigger second messengers such as cAMP, cGMP, inositol triphosphate)

steroid

testosterone, estradiol, estrogen, cortisol

slow acting changes DNA expression, can also have nongenomic effects in the brain which are fast-acting

HPG axis

longer day length: higher levels of GnRH released from Hypothalamus, signals pituitary to release LH, releases T from gonads, changes behavior in brain

HPA axis

hypothalamus (CRH) - pituitary (ACTH) - adrenal cortex (cortisol) - negative feedback on hypothalamus

testosterone effects

aggression, suppresses parental care, increases activity level, suppresses immune system, promotes sperm production

activational effect (hormones)

changes trigger behaviors in adults, temporary, act on established structure

organizational effects

long-lasting, critical periods, establish substrate for future behavior

overall fitness equation

total # offspring = lifespan x # mates per year x # offspring per mate

intrasexual competition (secondary sexual characteristics)

influences # mates per year — direct competition between males within a species (weapons, defenses, fighting ability, bluff displays, stamina, indicators of strength, indicators of readiness to fight)

intersexual competition

influences # mates per year — individuals of opposite sex determine mating success based on preference (indirect competition between males)

Bateman hypothesis

number of mates more variable for males

male reproductive success more variable than females

reproductive success in males was based on # of matings

Anisogamy

male and female gametes are different sizes and contribute differently (different costs to mate)

critiques of Bateman (Gowaty)

Bateman overestimated subjects with zero mates (due to recessive lethal alleles in his crosses), underestimated the number of males with 1+ mates, therefore biased estimates of offspring numbers

critiques of Bateman (general)

there are costs beyond gamete production (parental care), skewed sex ratios (different # of males and females)

social monogamy (mating systems)

who pairs up and raises young together

genetic monogamy (mating systems)

who actually sires the offspring

how to determine paternity?

shared DNA length variations of microsatellites (ATATATATA)

direct benefits (mate choice model)

food resources, good parent, healthy mate

good genes (mate choice model) and handicap hypothesis

male secondary sexual traits may indicate good traits about an individuals fitness (honest indicator) or the trait could indicate good survival despite having it (handicap)